Furnace hearth



Sept. 1, 1931. G. c. MccoRMlcK 1,821,658

FURNAGE HEARTH Filed April so, l1350 2 sheets-sheet 1 w m s"`\ l 851, ffmauf/ mima Patented Sept. 1, 1931 narran STATI-:s

PATENT OFFICE GEORGE C. MCCRIJIICK, 0F NEEDHAM, MASSACHUSETTS, ASSIGNOR TO GENERAL ALLOYS COMPANY, OF BOSTNQV MASSACHUSETTS, A GGRPORATIQN F MASSA- CHUSETTS Application led April 30, 1930.

My invention relates to improvements in furnace hearths, such, for hexample, as hearths of heat treatment furnaces.

The principal object of the invention is the provision of hearths of furnaces for heat treatment and the like `having' a bottom made of cast plates so arranged and constructed as to permit free expansion and contraction in 'response to temperature changes without causing distortion, warping, buckling andthe like. n

According to the present invention, the furnace hearth is composed of a plurality of sets of elongated plates arranged in tandem with means for supporting and anchoring each set 'of plates at one end thereof, and with expansion joints formed between the plates in adjacent sets arranged to permit expansion and contraction, while keeping the several plates constituting the furnace hearth in correct alignment.

Other objects of the invention will appear in connection with the following description of constructions embodying the invention, and which are intended for illustration and not for limitation of the invention.

In the accompanying drawings:

Fig. 1 is a transverse sectional viewof a hearth within a furnace, the latter also shown in section. j

Fig. 2 is a longitudinal sectional View on line 2-2 of Fig. 3.

Fig. 3 is a plan view of thehearth shown in Fig. i.

Fig. 4 is an enlarged cross-section on line 4 4 of Fig. 3.

Figs. 5, 6, 7 and 8 are views of a modiied form generally similar to Figs. 1, 2, 3 and 4,

respectively.

The hearth erally are pre erably constructed of a heat resistant alloy such as a chrome-nickel-iren alloy which is resistant to scaling away at high temperatures.

K Reference numeral l() designates one set of elongated hearth plates, and 12 a second set of hearth plates arranged in tandem with plates 10, and there may be as many such sets of hearth plates as required'to make up a furnace hearth of the desired length.

lates and furnace parts gen- FURNACE HEARTH Serial No. 448,468.

The plates in the several sets are arranged horizontally and parallel, and are spaced apart as indicated at 14to permit gas circulation, heat travel, etc.

The side plates 10 and 12 nearest the furnace side walls are provided withy upwardly extending side boundary means 16, for retaining containers or parts being treated upon the hearth, and which may be obtained by making such members l0 `and 12v of substantially angle formation, but the wall portion or leg 16, .while providing Va substantially continuous boundary wall is preferably divided into flange lugs 18 spaced at relatively close intervals, as indicated at 20, so as to avoid distortion upon being subjected to extreme temperature changes.

Each set of plates is preferably anchored to the furnace floor and supported thereabove at one end, as for example, plates 10 are'shown provided at that end farthest from plates l2 with countersunk holes 22 for attachment of suitable anchoring supports (not shown)v but which may be constructed in any desiredv way, preferably l r of plates 12 adjacent to plates 10 comprise a pair of flat legs 26, and the transverse connecting portion 28, said 'portion 2S being provided with upwardly extending perforated side lugs 30, 30. i

The connection of plates 12 to anchor supports 24' is preferably made by bolts or rods 31, extending through the openings in the side lugs 30, 30 of anchors 24, and loosely inserted through holes in lugs 32 extending downwardly from the under surfaces of plates 12.

The plates 10 and 12 are connected by an expansion joint so constructed as not to` produce a material break or interruption in the hearth surfaces, and such joint is preferably obtained by providingthe ends vof plates l0 with a central tongue 34, which is slidably received in the slot 36 in plate.

V12. From the under side of tongue 34,

integral lugs 38y projectL downwardly, be-.

tween the lugs 32 of plates l2, and said lug 38 is provided with an elongated slot 40 throu h which the bolts or rods 3l are passe In this way the ends of plates l adjacent to plates 12 are anchored down, but can expand or contract freely .with changes in temperature.

In the modified form of Figs. 5 8, the hearth plates a and 12a are provided with a narrow top flange 42 on either side and the spaces between the bars are covered by inverted shallow channel bars 44, 46, malring a continuous hearth free from open passages between the component plates. With such modifications the slot and tongue arrangement of the expansion joint can advantageously be reversed to thereby avoid unduly large openings through the plate hearth. Thus channel bar 44- superposed upon plates 10 may be provided with slots 48, and channel bar 46 superposed upon plates l2 provided with tongues 5() to be slidably received in said slots 48. Instead of providing the bars with top fianges 42, same may be omitted, and the channel bars 44, 46 held against transverse displacement by lugs 52 projecting upwardly from the plates at the ends thereof. `In such form the anchors 24 may be extended across several plates, as indicated in Fig. 8.

Changes and modifications which may be resorted to within the scope of the appended claims are included within my invention.

I claim:

1. In a furnace hearth, Aa number of spaced apart horizontally arranged plates set parallel to one another and forming the main floor portion thereof, means for forming a wall ateach side of the same, an additional hearth portion also composed of a plurality of spaced apart parallel flanged plates, and side enclosure walls for the last named portion-tof the hearth, the two sets of said plates being connected by expansion joints.

`2. In a furnaceA hearth, sets of elongated plates arranged. in tandem, the plates of each set being substantially immovably supported and anchored in the neighborhood of one of the ends thereof, and having an expansion joint connection on the oppositey end thereof with the neXt adjacent set of hearth plates.

3. In a furnace hearth, a plurality of sets i of elongated hearth plates arranged in tandem, and means at the junction between adjacent sets of plates for holding one set of `plates substantially immovable and for restraining the adjacent end of the otherA set `of plates against vertical movement while permitting longitudinal movement of the last-named plate ends with respect tothe other immovable hearth plates.

4. In .a furnace hearth, a series of sets of elongated horizontally disposed parallel hearth plates, means whereby the meeting ends of adjacent sets of plates can expand and contract past one another, lugs extending downwardly from the plates of each set at the region of meeting, anchor supports for said plates and pins extending through openings in the side lugs and anchor members. Y

5. In a furnace hearth, a plurality of sets of hearth plates, means for anchoring one end of the plates of each set and an expansion joint between the opposite end of the plates of said set and an anchored end of the succeeding set of plates.

6. In a furnace hearth, a plurality of sets of elongated furnace plates, means for anchoring and supporting the plates in the several sets at like ends thereof, and expansion joint means between the free ends of the plates of each set and the anchored ends of the plates of the succeeding set.

7. In a furnace hearth, a plurality of sets of furnace plates, anchor supports for one end of a set of such plates, and lug and pin means for connecting the sets of plates to such anchor supports, and tongue and slot expansion joint means between the meeting ends of adjacent sets of plates.

In testimony whereof, I have signed my name hereto.

GEO. C. MCCORMICK. 

